| Summary: | 碩士 === 嘉南藥理科技大學 === 化妝品科技研究所 === 98 === Physicochemical properties of vesicles composed of phosphatidylcholines with different saturated degree, namely hydrogenated soybean phosphatidylcholine (HSPC) and egg phosphatidylcholine (EPC), adding with dioctadecyldimethylammonium bromide (DODAB) are investigated. The vesicles were characterized by means of determination of size distribution, zeta-potential analysis, and the storage stability. Mixed HSPC/DODAB and mixed EPC/DODAB cationic vesicles carried out fluorescence polarization examination to study effect of DODAB on molecular arrangement of the lipid bilayer. Differential scanning calorimetry (DSC) was used to investigate the phase transition behavior of vesicles. Transmission electron microscope (TEM) has been used for observation of vesicles structure directly. Furthermore, surface pressure – per molecular area (??A) isotherms of mixed HSPC/DODAB and EPC/DODAB monolayers at the air/water interface and area relaxation curves fixed at a surface pressure of 30 mN/m were measured at 24℃ to understand molecular interaction between PC and DODAB. Finally, a reliable vesicles formulation was selected to arbutin and in vitro skin penetration efficiency of vesicles-arbutin was evaluated.
Adding DODAB into HSPC and EPC vesicles increased storage stability, decreased of particle size and size distribution, and showed positive zeta potential. Adding DODAB into HSPC vesicles does not changes membrane bilayer fluidity, and the main transition temperature of vesicles was increased as XDODAB from 0 to 0.5, and then decreased as XDODAB >0.5. But incorporation of DODAB into EPC vesicles increased main transition temperature and decreased the membrane bilayer fluidity. Mixed HSPC/DODAB vesicles dispersed in different concentrations (2 mM, 20 mM and 200 mM) of phosphate buffer saline is unstable. The stability of mixed EPC/DODAB vesicles dispersed in 2 mM phosphate buffer was better than that in 20 mM and 200 mM phosphate buffers. The ??A isotherms indicate that HSPC/DODAB and EPC/DODAB monolayers were miscible respectively at the air/water interface. Area relaxation curves fixed at 30 mN/m expressed that HSPC/DODAB 5/5 and 7/3 monolayers showed more stable kinetically. In the presence of arbutin, membrane bilayer fluidity of HSPC/DODAB vesicles was increased, but that of EPC/DODAB vesicles was decreased. The entrapment efficiency of PC/DODAB vesicles encapsulating with arbutin decreased as molar ratio of DODAB increased.
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